Electron Microscopic Studies on the Nuclear-Polyhedrosis Viruses of Several Lepidoptera

Abstract

Thin sections of epidermal cells of the larvae of Antheraea pernyi GUÉR.-MEN. and Samia cynthia pryeri BUTLER infected with the nuclear-polyhedrosis viruses revealed some of their developmental stages. In the early stage of infection, a chromatin mass appeared in the center of the nuclei to which many virus rods attached. These rods were released into the surrounding nucleoplasm, where the rods acquired developmental membranes singly or in groups of up to 14. The membrane-covered rods became enclosed within polyhedra. In the late stage of infection the central chromatin mass dissappeared and the nuclei were filled with many polyhedra. The nuclear-polyhedrosis viruses of A. pernyi and Bombyx mori were experimentally transmitted to S. cynthia pryeri. These viruses retained their morphological characteristics even if they multiplied in the new host.
The nuclear-polyhedrosis virus of Hyphantria cunea DRURY was larger in size than the viruses of A. pernyi and S. cynthia pryeri. There were from 2 to 14 rods within one developmental membrane.